Just six months after Chinese and American leaders reached a new agreement allowing more foreign movies into the world's most populous nation, officials there are trying to torpedo the box office returns of some of Hollywood's biggest summer films.

American studios carefully schedule their pictures' launch dates — often declaring them a year or more in advance — to avoid colliding with similar movies going after similar audiences. But the state-owned China Film Group, which oversees the release of imported movies, has been scheduling U.S. films from the same genres on the same dates, aiming to limit their total grosses and boost the percentage of box office generated by Chinese-made pictures.